Presently available gas pumps for microanalytics are relatively large and use mechanical actuators that are subject to wear and limited service life. The use of mechanical actuators creates undesirable flow pulsations that can only be reduced through bulky buffer volumes. The difficulty of fabricating and assembling such mechanical pumps is significant and contributes to their high price.
Ion drag pumps overcome many of the deficiencies of mechanical pumps. Ion drag pumps first ionize a gas and then use an electric field to attract the ions. As ions are pulled along by the electric field, they also drag along other neutral gas molecules.
As the ions progress away from the point of ionization, the ions tend to recombine. However, by that time other ions have been created at the point of ionization that continue to push the recombined ions along, thereby continuing the flow of gas.
While ion drag pumps are an improvement over mechanical pumps, they are still relatively inefficient because of the rapid rate of recombination. Accordingly, a need exists for improved pumping methods for microanalytic devices.